Diaphragm.



w. N. DENN/LSQN:

DIAPHRAGM.

APPLICATION FILED APR. 18. 19.12.

fifa l i Arromv'sv WITNESSEQ w. N. DENNISON.

DIAPHRAGM.

APPLICATION FILEDAPR. I8, 1912.

Patented June 2 7, 19N?` 2 SHEETS-SHEET 2.

, By /vmi MW AT1-DEWEY Lio UNITED STATES PATENT OFFICE.

WILBURN N. DENNISON. OF MERCHANTVILLE, NEW JERSEY, ASSIGNOR TO VICTOR TALKING MACHINE COMPANY, A CORPORATION OF NEW JERSEY.

DIAPI-IRAGM.

Specification of Letters Patent.

Patented J une 27, 1916'.

To all lf2/mm if may mm'crn lie it known that Il, Yl'naafux N. Dnxxison, a citizen of the United States, and a resident of Merchantville. in the county, of Camden` State of New Jersey, llnited States of America, have invented certain new and useful lnmrovements in Diaphragms, of which the following is a full, complete, and exact disclosure.

My invention relates to diaphragms such as are particularly used in sound recording and reprmlucing machines` such as talking machines` phonographs and the like.

The objects of my invention are, to produce a diaphragm which is more sensitive than those ordinari-ly found in sound recording and reproducing machines; to produce a purer and more perfect reproduction of sound than that ordinarily obtained; to obtain a reprmluction of sound which is sub slanlialliv identical with the original sound recorded in the sound record tablet: to enhance the'delail, quality and volume of the, sound reproduced lfrom a sound record tablet; and to eliminate lo a `great extent the pronounced vibration or throbbing` often occurring during the reprodiwtion of sound from a sound record tablet.

Further objects of my invention are, to subject every point in the vibratory portion of a diaphragm lo a strain or tension acting` at that point in a direction radial to said diaphragm; to impose upon the iieXible vibratonv part or portion of a diaphragm substantially uniform and equal radial strains and tensions; to impose upon the vibratory part of a diaphragm an initial radial tension. and to retain said portion in that condition of tension; to provide a unitary diaphragm structure in which an initial radial 'tension to which the vibrator-y part as originally subjected is retained o1' continued or maintained by a substantially unyielding rigid ring or rim substantially unitary with said vibratory portion; and to apply tothe vibratory portion of a diaphragm a rigid unyielding rim or edge; to impose upon said vibrator-y portion a substantially uniform radial tension; and to,`

maintain the diaphragm by said rim int-hat condition.

Other objeets of my invention appear in the specification and Claims' belowf of this specification, and in which the same reference characters are employed to designate the same parts throughout the various views, vFigures l to l indicate in a diagram-4 Fig. 7 is a cross sectional view of a sound box in which my improved diaphragm is mounted; Figs. 8 and 9 are a .fragmentary sectional view taken in a plane at right anlies to the axis of the diaphragm and a frag mentary sectional view taken in a plane Coincident with the axis of the diaphragm, respectively, of a modified form of thisinvention: Figs. l() and 11 are a fragmentary sectional view taken in a plane at right angles to the axis of the diaphragm and a fragmental-y sectional view taken in a'plane eoincident with the axis of the. diaphragm, respectively, of a second modified form of this invention; and Fig. l2 is a fragmentary front elevation of the modified form of diaphragm shown in Figs. l() and 1l.

Referring first to the method or process of making my improved diaphragm as particularly illustrated in Figs. 1 to 4, I first form in an)y suitable manner a disk 1, of any suitable flexible elastic vibratable materia'l. This disk may be of mica, metal, or any other material which may be vib ated eitherl by or in accordance with impulses corresponding' to sound waves. I also form a ring or rim or annulus 2, substantially C-shaped in .cross section, said ring being substantially` `elliptical. on the outer or peripheral ed of the same, and having the slot or opening 3 on the inner Aside thereof. The ends 4 of the v., aid C-shaped section are preferably thickened to provide cylindrical surfaces 5 5 on the inner side thereof. I also provide a die 6,'Composedof tWo portions, whieh for convenience will be referred to as the lower portion or part 7 and the upper portion or part 8. These two portions or parts 7 and 8 are substantiallyidentical With each other, each being provided with av substantially semi-circular groove 9 in the adjacent faces thereof. I'next place Within the slot or opening 3 in ,the ring 2 a suitable amount or layer 10 of cementitious Referring to the drawings 4forming a part material, such as shellae, Water-glass, or other cement, and place the said rngm construction,4 and the center of the diaphragm is connected in any usual manner, as by the connecting rod or bar 21 with the inner end 'of the stylus bar 22 pivoted at 23 to the sound box l).

A diaphragm made ii'i the manner above set forth gives a remarkably pure tone of reproduction of great volume and excellent quality, and the reproduced sound is exceedii'iglyy pleasant and free vfrom those objectionable rhythms or tlirobs or vibrations of great amplitude frequently occurring during the.reproduction of sound from a sound record tablet.

Although this invention is not to be construed as being limited to the employment oi' a cooling 'tiuid oif any predetermined teniperatuie, or to the use oi thediaphragni so formed for the reproduction of soundat any predetermined ten'iperature, it has been found that when the diaphragm is made between 'the parts or portions of dies such as are above described, iii which is circulated a cooling tiuid i'iiediuniof about 32" It., and

the diaphragm so formed is used in the reproduction of sound ft'roiii'a sound record tablet at a temperature oit' around (t)O F., and even up to normal atmospheric temperatures, a reinarhably tine quality ot reproduction of sound is obtained. it has been suggested that these results are probably due definitely state.

to the differences in the expansion olI the materials employed. and perhaps also to the cross sectional shape ,of thel ring; that. the

expansion of the ring causes the ring to grip the periphery of the disk even more trmly than it did at the lower temperaturi: and that the radial expansion of the metallic ring being greater than that oi the mica disk causes the ring to increase the radial tension on the disli at the higher temperatures. The tuil extent yto which these tactors may vary and improve the quality o'tE the reproduced sound, am unable at'the lnesent time to My invention, however, contemplates a diaphragm structure in which the vibratory portion and the rigid rim expand at ditterent rates under a, rise ot' temperature, and therefore the action of the rim.

' will be to maintain the vibratory portion under tension at any teiiipeiature above that atwhieh .the two said portions of the diaphragm are united.

This invention may also be embodied in various other forms than the one hereinbe- For instance` as illustrated fore described. iii Figs. 8 and t), the circulardiaphragm 25, instead oi being tensioiied by a continuous marginal annular ring or rim 2. as hereinbefoi'e de:-scribedl is teiisioned by means of a plurality, preferably three or more of ring or rim sections oi.' segments 2o spaced equally around and' securely clamped to the marginal portion o'lt the diaphragm 25. These ring sections 2o are preferably clamped in place `by meansjot a die or dies, as liereinbefore described` the ring sections being preferably filled with cementitious material7 as in the case ot the ring or rim 2 liereinbet'ore describcd rl7he rin sections are preferably the same in cross section as the rim 2f liereinbefore described. The outer central portiolrot each segment 2h is provided with a radially extending threaded aperture ZTin which is threaded an adjustable tensioning screw 2H which extends outwardly loosely through an aperture 2t! provided thereior in the sound box casing 1t) and loosely through a spring or other yielding member 31. which engages against the outer surface oi the sound box casing. The

'Y screw .28 is providcdwith a slotted head 252 which engages against the outer surface ot the yielding member Si] and the yielding member 31 normally tends to press the screw 2S outwardly through the casing EN), thus in coiipei'ation with the other similar screws and yielding members, producing an outward tension on the diaphragm 2.7L which is -thus held in a state ot radial stretch or tension. the screws being adjustable .to vary the stretch or tension. The diaphragm 25..ln

this instance` is supported as hercinhetorc.

bei'ore described. by screws 2S and yielding,

members 2t). Each tab tio is preferably provided with a central radial slot 37 toy permit ot the troc movement of the corresponding screw 2t). Each tali is also preferably provided with a plurality of apertures 38 in which the cementitious material engages to anchor the tab to its segment. The diaphragm in this latter instance is also prefkets 20, as hereinbefore described. This invention is not limited to any speciic method or to any specific construction.

"erably.mounted between two yielding gasas various changes mightl be made both in the method and eonstruetioii, without departingfrom the spirit o'l the invention or the scope olt the appended claims. Thus the size or diameter of the grooves l-,l in the die 1l may he slightly larger than that o'l2 the grooves 9 ir` Vthe die (i, out of the same size and shape in eross seetion, in which event Ythe ring' 2 would be stretched or eX- panded throughout when pressed in the die ll as distinguished from being stretched or expamled on the inner side thereof merely as previously described, and the stretching" or expanding of the entirel riujg; 2 would,` in the same manner place the i'ibratory por4 tion of thel diaphragm under a radial streteh or tension.

imongr other things it has been tound that -diaphragnnsl placed under radial tension as above deserilied return to their normal or neutral positions very much more (piiekly than do diaphragme: not under such tension, and that they are more .sensitive and more perfeetly expansive to impulses, correspondung to sound wares, impressed upon the same, than are diaphragms which are not suhieeted to radial tension.

llavinggj thus` deseribed my invention, what l claim and desire to ,protect by Letters Pateut ol.E the United States isi:

Il. A unitary diaphragm comprising a Yibratory portion and a rim engaging opposite sides oi said diaphragm and lixedly seeured to the periphery of said vibratory portion, every point in said Vibrator-y portion having a radial tension imposed thereon by said rim alone.

2. A unitary diaphragm Comprising a viliratory portion and an integral ring; tixedly secured to the periphery of said vibratory portion and symmetrically disposed on opposite sides of the plane oi,E said diaphragm, every point in said ribratory portion hai7` ing,r a radial tension imposed thereon by said rim alone.

A, diaphragm comprising a Vibratory radially stretched portion and a slotted ring, the i'ierii'ihery of said vibratory portion being rigidly clamped in the slot of said ring and placed and held hy said ring under radial tensionu -l-. It unitary diaphragm eomprising' f bratory portion and an integlral rim enjJ." ring opposite sides ol' and i'ixerelly sernrefl to the periphery of said ribratory portion, every point in said vilnatory portion hay ing' a radial tension imposed thereon by said rim alone.

U5. ,l diaphragm Comprising a Vihratory portiliin and a `slotted n'ietallie ring, the periphery ot said i'ilu'atory portion being rigr` idly elamped in the slot in said ring and placed and held hy said .ring alone luider radial tension.

(L diapliraffni eoniprira'ngv a vibratory diSland a slotted ring', the periphery ot' said dish being clamped by said ringr in said slot, the edges ol. said slot being forced into and below the planes oil' the adjacent vt'aees oi said disli and holding said ribretory diskv under radial. tei'ision,

'i'. diaphragm comprising ii vibratory dish and a i Vid rii'i'g provided with a eireumferential slot on the inner side thereof, the edges of said slot holding the periphery oi said disk ripilly clamped between the same and holding said vibratory poi under `adial tension.

il diaphragui eomprising a. Yiliratory portion and a metalli:J ring, the periphery of said vibratory porti on being elamped by said ring, said ribratmy portion being. placed by said ring under radial tension.

f). A diaphragm eomprising a rihratory dielf and a slotted riiig, the perillihery of the disk being clamped by the ring in said slot, the interior ol said ring being filled with a cement, said vibratory'disk having,r a radial tension imparted thereto by said ring alone.

l0. A diaphragm cou'iprising a radially stressed portion, a, ring uniformly disposed about the edge thereol'l which edge is clamped' by said ringY whereby said dia-l phragm is plaeed and held hy said .ring un der equal tension on the 'respective sides thereof.

in witness whereof, I have hereunto set my hand this 16th day of April, A. l). 1912.

ll/ILBURN N. DENNlSUi. Witnesses z FRANK B. MiDnLE'ioN, i r., Hanni' (loan lrx man. 

